NUTS AND VOLTS

Posted in: Developing Perspectives

Leaded Components: Reports of their death have been greatly exaggerated.

January 16  Bryan Bergeron

I’ve been reading and writing about the imminent demise of leaded components for decades. Even so, at least half of my work still involves leaded components. After all, what’s not to like? Leaded components are easy to work with. It’s easy to identify the value of a leaded resistor or capacitor with the naked eye, and leaded components are readily available.


Besides, I’ve already committed the band values — red for two, orange for three, yellow for four, etc. — to long-term memory. Then, there’s the muscle memory of how to bend leads and how to work a soldering iron tip around the porcupine-like mass of leads when the component side is down.

Why let all that learning go to waste?

I don’t know what I would do without a good supply of 1/4 watt 10K leaded resistors to use as circuit probes. When I’m working with an Arduino or other microcontroller board, it takes only a few seconds to wire-wrap a 10K pull-up or pull-down resistor to an I/O pin. Try that with a surface-mount (or SMT) resistor.

Then, there’s the differential in infrastructure cost and workbench real estate. For leaded components, I have a simple Weller temperature controlled soldering iron, good old-fashioned needle-nose pliers, and desk lamp magnifier.

For surface-mount work, I have a hot air station that has the footprint of an oscilloscope, a tool drawer full of tweezers and stainless steel picks, and a half dozen containers of various solder pastes and fluxes.

And forget the magnified desk lamp — I have to don a Bosch & Lomb stereo magnifier and get my nose within inches of the board to see what’s going on.

One sneeze, of course, and every SMT component not glued or soldered down will be forever lost in the dust balls behind my workbench.

I know that experimenters aren’t alone in the battle between SMT and leaded components. I routinely tear down equipment for both fun and profit, and it’s unusual to find an electronic device devoid of leaded components.

Many of the inexpensive devices made in China — from drone controllers to electronic measuring devices — are made with a mystery chip embedded in a black epoxy blob that is surrounded with leaded capacitors and resistors.

This is understandable, given the cost of converting an electronics assembly plant from leaded to SMT devices. Unless you’re building iPhones or electronic watches, why upgrade an assembly plant unless you have to?

The bottom line is that if you’re just getting into electronics, don’t be dismayed — or distracted — by the world of SMT. A traditional perfboard, a good supply of leaded components, and a few schematics to work from will get you started.

When you’re ready to make your circuit semi-permanent, then break out your soldering iron or wire wrap tool. SMT components, the special boards, pastes, and the rest will be there if you ever need them.  NV


Posted on 01/16 at 9:45 am

Posted in: Developing Perspectives

Easing Into STEM

December 15  Bryan Bergeron

I’m often asked what the best way is to support STEM (Science, Technology, Engineering, and Math) education with electronics. At the high school level, as soon as I start talking about Arduino boards and sensors, teachers tend to run away. It’s intimidating to set up an electronics workshop from scratch. Think of all the necessary infrastructure that needs to be constructed — from multimeters and soldering irons to parts bins — and the components to fill them.


An alternative to a “made from scratch” approach is to use a kit or system that’s been preconfigured with sensors and the tools to collect and display the data in real time. I’ve used TechBasic ($15; ByteWorks.us) to turn my iPhone into a data collection platform.

I’ve gone as far as taping my phone to the spokes of my bike during an off-road excursion. The concern, of course, was losing my phone. As I’ve discussed in previous editorials, TechBasic enables you to access the various sensors in the iPhone, display the data graphically, and massage the data as you see fit — all using a variant of the BASIC language. I’ve seen videos in which users tie their cell phones to kites and even solid fuel model rockets.

A way to get your hands on data without putting your phone at risk is to use a wireless sensor such as the PocketLab ($98; thepocketlab.com). The 2.5” x 5/8” x 1-1/8” device is a BlueTooth-connected sensor cluster that collects data on temperature, barometric pressure, magnetic field, angular velocity position, and acceleration. The PocketLab is based on the TI CC2541, which I’ve used in the form of a fob-based evaluation kit available from Texas Instruments (TI). I found the hardware promising, but the software severely lacking. TechBasic provides support for the TI fob if you’re into programming.

The folks at PocketLab also addressed the software problem, adding in support for cloud storage/sharing — the real advantage of this device over TechBasic. Not only are data displayed in real time, but they automatically move from the PocketLab to your Android or iOS device to the cloud, where data can be downloaded to your laptop for evaluation, manipulation, and analysis.

Also, while the TI fob is a bit clunky, the PocketLab’s easy to handle plastic enclosure is mainly air, and the largest heaviest component by far is the coin battery. As an aside, PocketLab is one of those KickStarter success stories, raising $100K in the time they had hoped for $20K.

So, with environmental recorder in hand, what is one supposed to do to get all of this exposure to science, technology, engineering, and math? Well, as long as the experiment can be contained within the range of a Bluetooth device — say, in a classroom or on your person if you’re outside — it’s up to your imagination.

I wish I had access to a sensor-packed cell phone or an affordable wireless sensor package when I was studying Physics. I can still remember writing down rows of numbers from acceleration experiments. And forget about graphing results. That took hours.

So, in theory at least, with all the drudgery gone from doing science, everyone should be free to exercise their creativity, instead of spending time filling notebooks full of data. If you’ve used data collection and analysis as part of your STEM curriculum, please consider contributing to the reader forum so that other educators can learn from your experience.  NV


Posted on 12/15 at 1:34 pm

Posted in: Nuts and Volts

Sensor to Avoid Crowds

December 15  Jeff Eckert

Let’s say you’re one of those folks who doesn’t like crowds and hate standing in line. As a result, you often decide to stay home to avoid the frustration of waiting for a table at your favorite restaurant, fighting the hoards for sale items at Macy’s, or bumping up against a herd of sweaty people at the gym. If so, you’ll be happy to hear about a new device from recent startup, Density (www.density.io).

The Density IR sensor is a basic people counter that — installed at the entrance to a public place — keeps track of how many people have entered and how many have exited, thus allowing it to provide both real time and historical data to help you decide when and if to drop in. Gathered information is collated by the Density Application Programming Interface and transmitted to a web application for use by a custom app.


For example, a company team is installing them in UC Berkeley gyms and other workspaces, and a Sacramento-based outfit called Requested (requestedapp.com) uses the system to generate restaurant discounts during off-peak periods. It doesn’t appear that a significant number of locations have Density installed at present, but who knows? It could catch on — especially given that hardware and installation are free. There is a monthly fee of $25, however, to use Density, but if it generates even a few extra customers, it seems well woth it.  NV


Posted on 12/15 at 1:50 pm

Posted in: Nuts and Volts

Build The Incredible Christmas Tree Dipstick!

December 15  Russ Shumaker

Checking the water in the Christmas Tree need not require laying upside down getting poked in the head by pine needles!
 

It was Christmas afternoon. The gifts had all been opened, and a substantial brunch had been consumed. The members of the household were all off doing their various things. The resident techie was wandering around the house with his new Dremel® tool, looking for something to grind, buff, drill, polish, or otherwise fold, spindle, or mutilate, when a voice called to him from somewhere in the house.

“Hon, have you checked the tree, lately?”

This was wife code talk for, “Add water to the Christmas tree, now please.”


Read the article now!


Posted on 12/15 at 6:03 pm

Posted in: Developing Perspectives

For Learning, Old School Can be the Best School

November 15  Bryan Bergeron

When I started out in electronics, my “junk box” of rescued parts from TVs, radios, and the like was the source of endless projects and test instruments. Armed with a few key texts — especially the ARRL Handbook and Getting Started in Electronics by Forrest Mims — just about anything was possible.


Sure, my projects didn’t win any beauty contests with labels made with a permanent marker and reused chassis with dozens of extra holes, but most worked — eventually. It’s the “eventually” part that’s key.

I can recall dozens of blown circuit breakers, exploding electrolytic capacitors, and shorted vacuum tubes. However, I also recall the satisfaction of seeing copper, carbon, and steel come to life.

With time and savings, I later could buy just about anything that I wanted — from commercial test gear to top-of-the-line ham radio equipment. It made for a great looking test bench and ham shack, but I lost out on the learning end of things. It didn’t matter that I could read the schematic of the hermetically sealed phase locked loop synthesizer in my communications transceiver — I could never really know it. I could replace it if defective, but not really fix it the way I could one of my old creations.

From a practical perspective, having a nice portable o-scope with high bandwidth and Flash memory storage makes debugging a pleasure. Then, there’s the safety issue — none of my creations were UL listed or approved.

So, there’s nothing wrong with new gear that’s compact, safe, and easy to use. It’s just that — from an experimenter’s perspective — shiny commercial equipment can become a black box. I make a habit of disassembling everything I buy; in part to understand what’s in the black box, but it’s still an imperfect exercise.

If your goal is to maximize the learning experience — whether for yourself or someone you hope to pass on your knowledge of electronics to — then I’d consider the old school “junk box” approach to learning. Fill your box with parts from tear-downs of whatever you can get your hands on. It’s amazing what you can harvest from an old PC, for example. Even a discarded compact florescent bulb can yield a half dozen reusable components.

I’m fortunate to live a few miles from MIT, where there’s a regular flea market of used test gear and lab equipment that’s sold by the pound. Find out where your local ham or flea market is held and drop by at least once a year. Even if you don’t use parts harvested from the gear to build your own, the exercise of a tear-down is educational in itself.

You can’t wildly rip things apart, however. Take a methodical approach, trace the connections to see what components are associated with each other and — if you can — create a schematic diagram of the circuit in the device.

Lately, I’ve been partial to vacuum tube projects. With a few tubes and high voltage power supplies on hand, it doesn’t take much effort to build oscillators, tuners, sound effects devices, and so on. So, go ahead. Give the “old school” junk box method of setting up your workbench and your communications, robotics, or other projects a try. Your projects may not look as attractive as the commercial systems, but you’ll really understand the inner workings of what you build.

You’ll then be well on your way to being a real experimenter.  NV


Posted on 11/15 at 8:57 pm

Posted in: Developing Perspectives

Wanted: Magnetic Free Zone

October 15  Bryan Bergeron

Magnetics, for the most part, make life easier. Consider what we’d do without the solenoids that actuate electric garage door motors, the rare-earth magnets embedded in iPad covers, magnetized tools, and the ubiquitous kitchen refrigerator magnets. However, the magnetic fields associated with magnets can be problematic.


For example, one of my interests is rebuilding vintage mechanical pocket watches. If you own a mechanical watch, you know that a magnetized watch will run abnormally fast. Well, I have a pocket watch on my desk that constantly gains time. I was at a loss to understand how the watch could become magnetized simply sitting on my desk. Well, using an inexpensive pocket compass, I was able to verify that the watch was being magnetized by a pair of scissors in a drawer directly under the watch. Opening and closing the drawer several times a day was enough to magnetize the watch — just as running a permanent magnet over a screwdriver can transform it into a magnet.

The discovery with my pocket watch led me to search for a magnetic free zone in my house. It was, in short, difficult. In my office, I have a dozen super magnets to hold papers on my white board. Then, there’s the unshielded speakers on the wall. In my kitchen, I was surprised to learn that some of the flatware was magnetized. On my dresser, I found my steel collar stays and magnet sets. It seemed my compass never really settled on magnetic North, given the various motors and electronic gadgets around my place.

In retaliation, I purchased a few degaussing machines from eBay, where they can be had for about $10 and up. First up was the fixed magnet combined magnetizer/demagnetizer. These devices work great as magnetizers for long thin objects such as screwdrivers, but are useless in reversing the process.

Next, I tried the generic Chinese-built “blue box” demagnetizer — essentially an AC solenoid without the moving parts and a momentary on switch. You place the screwdriver or other object you want to demagnetize on top of the box and press the button, which energizes the core with 110 VAC. Then, you slowly move the object away from the unit as far as you can before releasing the switch. The iron molecules within the tool or other object should be randomly aligned, and therefore non-magnetic. This solution was affordable, reliable, and consistent.

Given that I was looking for a solution on eBay, I also had a serendipitous find — an old US made “instantaneous demagnetizer” tool by Magna Flux ($20). This tool uses a capacitor discharge to quickly ramp down the magnetic field after it’s been built up. Like the blue boxes, it did the job. Moreover, there is no need to move the object to be demagnetized while the AC field is energized. Just press and release the button. The capacitor circuit takes care of decreasing the magnetic field.

Of course, if you decide to demagnetize your tools and mechanical watches, set up a safe area away from anything remotely resembling a magnetic data store. Don’t think of using a demagnetizer around your credit cards or your DAT collection.

With the magnetics out of the way, I’m left to puzzle over why a mechanical watch would run faster when magnetized. Is it somehow more efficient because of decreased friction? Are Eddy currents somehow imparting energy to the mainspring? Could magnetized motors somehow run more efficiently? If you have the answer, please drop me a line. NV


Posted on 10/15 at 9:08 am

Posted in: Nuts and Volts

THE WORKBENCH CHALLENGE 2015!

September 15 

Back in 2008, Nuts & Volts sponsored the $100 Workbench Challenge. It was a great success and we had plenty of readers enjoy participating in the contest and showing off their carefully crafted work spaces. With the changes in available tools and technology, we decided to bring the challenge back, but this time even bigger and with a lot more prizes! Our new two-part contest is a combination of straight-up workbench design and a bit of "show and tell." So, let’s get down to details. What exactly is the Workbench Challenge 2015? Check out the details... 


Posted on 09/15 at 3:44 pm

Posted in: Developing Perspectives

Home Automation: Are We There Yet?

September 15  Bryan Bergeron

With Amazon’s general release of the Echo home automation controller, it may be time to take a second look at the home automation market. I first took the plunge into commercial home automation several years ago with X10-compatible hardware (http://www.x10.com). 


For the price of a bare-bones Echo ($180, www.Amazon.com), you can get a half dozen wireless timers and remotes for controlling lights, appliances, and your home security system. X10-compatible home automation devices are commodities — inexpensive, ubiquitous, and they work. Unfortunately, they’re also a bit boring.

At the other end of the home automation market are the cloudcompatible smart thermostats and cameras, typified by the Nest learning thermostat and Nest cam, respectively (www.nest.com). Both can be controlled through your smartphone from anywhere in the world. Plus, the learning thermostat is compatible with a variety of devices — from smart locks and sprinkler systems to ceiling fans.

If you want to make the Nest cam fully functional, you’ll have to pay a $10 monthly fee to Nest Aware — not something I’m prepared to do. 

One of the advantages of the Amazon Echo is that it’s compatible with Belkin WeMo and Philips Hue devices. WeMo is compatible with standard Wi-Fi routers and iOS devices, such as the iPad. Hue — which is primarily for lighting — also works with a standard Wi-Fi router, and both iOS and Android tablets and smartphones.

I’ve used the Philips Hue lighting system with my iPhone for about a year. It’s expensive, however, at about $200 for a Wi-Fi/Hue bridge and three 60W equivalent LED bulbs. Which brings me to cost. The basic “star trek” package — which allows you to say the equivalent of “Computer, lights on” from anywhere in your living room — is about $400 — $180 for the Echo and $200 for a basic Philips Hue lighting system. 

Add a few Belkin WeMo Wi-Fi switches for your existing lights or appliances, and you’re easily approaching $500. Still, this sort of off-the-shelf functionality that actually works was science fiction just a few years ago.

As Google, Apple, and now Amazon compete for the front end of the home automation market, there are likely to be more and more affordable peripherals and tools. More importantly — from an electronics enthusiast’s perspective — is the availability of inexpensive peripherals that can be easily torn down and repurposed for other uses. Think of replacing an RGB LED with three opto-isolators to control three servos, for example.

I think we just might have the “star trek” computer system of the 1960s. Now, someone needs to start working on the transporter, so we can say “Beam me up, Echo.” NV


Posted on 09/15 at 10:37 am

Posted in: Nuts and Volts

It’s not a Segway, it’s Sideways…

September 15 

Like a Segway, Sideway uses a lean angle to control speed. It uses a wireless Wii Nunchuk controller to manuover the two wheeled skateboard. The Sideway uses the Parallax Propeller with custom software for the IMU and control. There are two 280W, 24V electric scooter motors, one on each wheel, both driven by a Sabertooth 2x32A motor controller.  It'll run for about 40 minutes +/- on a single charge.


Hack-A-Day: Sideway

A quick video showing the Sideway V2. Sideway is a self-balancing electric skateboard, designed and built by Jason Dorie


Posted on 09/15 at 9:18 am

Posted in: Nuts and Volts

Nuts & Volts Newsletters

September 15 

For those who may not have known, we send out a Newsletter every week! If you would like to see one of our previous Newsletters, just click on one below or all of them. If you would like to sign up, just click the link at the bottom. 

Newsletter #1 Newsletter #8
Newsletter #2 Newsletter #9
Newsletter #3 Newsletter #10
Newsletter #4 Newsletter #11
Newsletter #5 Newsletter #12
Newsletter #6 Newsletter #13
Newsletter #7 Newsletter #14

Update
1/18/16 - Note that this page is not updated as new content becomes available. For a complete listing and links to all newsletters and their content, visit our newsletter page at www.nutsvolts.com/newsletters.




Posted on 09/15 at 1:04 pm

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